Coating and drying machine for alpha continuous sheet of paper and the like



April 1934- J. DUVALL 1,956,062

COATING AND DRYING MACHINE FOR A CONTINUOUS SHEET OF PAPER AND THE LIKE J Filed July 14, 1931 5 SheetsSheet l dmmm;

5 Sheets-Sheet 2 J, DUVALL Filed July 14 1931 April 24, 1934.

comma AND DRYINGYMACHINE FOR A CONTINUOUS SHEET OF PAPER AND HE, LIKE I mi wytl- J.DUVAL.L

April 24, 1934.

COATING AND DRYING MACHINE FOR A CONTINUOUS SHEET OF PAPER AND THE LIKE Filgd July 14, 1931 5 Sheets-Sheet 3 may/4%,"

i l I l II- J. DUVALL COATING AND DRYING MACHINE FOR A CONTINUOUS SHEET OF PAPER AND THE LIKE Filed' July 14, 1931 '5 Sheets-Sheet 4 mm u w w q Wi l-I l April 24, 1934. J, DUVALL 1,956,062

' COATING AND DRYING MACHINE FOR A commuous SHEET OF PAPER AND THE LIKE Filed July 14, 1931' 5 Sheets-Sheet 5 Patented Apr. 24, 1934 PATENT "OFFICE COATING AND DRYING MACHINE FOR A CONTINUOUS SHEET OF PAPER AND THE LIKE James Duvall, Camas, Wash.

Application July 14, 1931, Serial No. 550,647

.3 Claims.

[y invention relates to and has for its princw-al object the providing of machines for coating and drying a continuous sheet of paper of considerable length and for similar uses.

In the coating of a continuous sheet of paper with liquid adhesive, it is desirable that the adhesive coating be properly dried while the paper is traveling in the machine, so that it may be rewound into rolls at the discharge end of the machine, ready for conversion into gummed tape and the like; and the drying of the coating should be accomplished at the same rate that the adhesive coating is applied. The distance, or time, of travel of the paper through the machine stands in direct relation to the drying capacity of the machine.

Further, in order to maintain the distance, or time, of travel of the paper within practical limits, I have found that auxiliary means must be provided for accelerating the drying ofthe adhesive, namely, by passing a current of air, preferably heated, over the coated surface of the paper; and I have found it best to divide the said current of air into diverging branches; to direct one branch, heated to a higher temperature, over the initial end of the sheet, and direct the other current, heated to a lower temperature, over the final end of the sheet. Care must be taken not to over-dry the adhesive, and thus cause'it to become hard and brittle.

Therefore a further object of my invention is to provide means for controlling the humidity of the drying chamber and thus prevent excessive drying of the adhesive coating of the sheet. I

3 attain this object by circulating the air contained within the housing of my machine in such a manner that the air which is most humid is permitted to rise to the top of the air chamber, due to its lower density, and portions thereof allowed to escape, and I replenish the remaining volume of circulated air, by air admitted into the drying chamber from the exterior, at a lower level A further object of my invention is to prevent the sheet from curling up at its edges towards its coated side. Such curling might be'prevented by applying sufficientpull on the sheet to keep it straight and flat; but such pull would subject the sheetto excessive tension tending to break I it. I have discovered that curling of the edges may be prevented by drawing the sheet over an arched supporting surface.

To this end I employ two wheels of large diameter, alined in a vertical plane and spaced apart a substantial distance to give a suflicient distance of travel for the sheet, and support the sheet on a firm arched bridge between the points where it leaves one wheel and passes onto the other.

A still further object of my invention is to provide a compact machine adapted to dry a sheet of considerable length, for example of 150 feet, to occupy but a minimum of floor space, and so to arrange my machine as to provide an intermediate space exterior of the housing of the drying chamber in which to locate the parent roll of paper, the devices for applying the adhesive to the sheet, and the rewind roll close together so that the operator can watch both ends of the operation at the same time.

A further object is to provide a traveling carrier for the sheet that will permit the rate of travel of the sheet to adjust itself without hindrance or strain relatively to the rate of travel of the carrier, in case there should be a variation in speed between them at any time; and further to provide for the rewinding of the dried sheet without strain on the sheet in drawing off the parent roll.

The above described and incidental features of my invention, and the details of construction and mode of operation thereof are hereinafter fully described with reference to the accompanying drawings.

In the drawings:

Fig. 1 shows a side elevation of my machine with the sheet carrying elements shown in broken lines and with portions of the housing broken away to disclose the details of construction;

. Fig. 2 shows a diagrammatic view of the driving connections for my machine;

Fig. 3 shows a vertical longitudinal section of my machineand further illustrates the relative arrangement of the sheet carrying elements and the air blast tunnels;

Fig. 4 shows a view of the interior wall of one of the said tunnels taken on the line 4 in Fig. 3, and illustrates the arrangement of the vents;

Fig. 5 shows a fragmentary, enlarged view of one of the wheels of my machine over which the sheet carrying elementsare carried;

Fig. 6 shows an enlarged fragmentary longitudinal sectional view of the web carrying chain shown in Fig. 5;

.Fig. '7 shows a section taken on the line '7'7 of Fig. 5 and illustrates the details of construction of the wheels upon which the sheet carrying elements are supported;

Fig. 8 shows a section taken on the line 8-8 of Fig. 6 and illustrates the construction of the roller bars shown in Fig. '7; Y

Fig. 9 shows a rear elevation of my machine and .illustrates the arrangement of the return and supply air conduits for the air tunnels;

Fig. 10 shows an end elevation of my machine with parts broken away to illustrate further details of construction;

Fig. 11 shows a plan view of my machine with portions broken away to illustrate further the arrangement of the sheet carrying elements; and

Fig. 12 shows a view similar to Fig. 11 with a portion of the walls of the air tunnels broken away to illustrate how the paper sheet is carried thereby.

Referring now to Figures 1 to 8, my coating and drying machine comprises a housing a constructed to provide two chambers b, 0, connected at the top by a passageway e, such construction forming between them a machine and working space d in which are located the adhesive applying means and the paper rolls.

Large wheels g, h, each comprising similar spaced wheel members g, having rims 9 see Fig. '7, are provided in the chambers b and c, respectively, and are supported on the framework p of the said housing.

Endless chains .9 constituting my sheet carrying elements are arranged over the rims of the wheel members g, h and pass from one wheel to the other through the connecting passageway e over idling rollers 2 located therein and return at the bottom over driven sprockets 3, 3a, which are journaled on the framework p in the upper part of the space d so as not to obstruct the latter. The sprocket 3 is connected with the sprocket 3a by a chain 3b and is driven by a chain 30 riding over a sprocket 3d mounted upon standards 3e and driven by a chain 32' from a suitable electric motor 3f as diagrammatically shown by Fig. 2. The motor 3] also serves to drive the adhesive applying rolls hereinafter described, by a chain 39 and sprocket 3h. The chains s upon return from the chamber 0 to the chamber b pass through openings r in the housing walls.

The chains s are connected by roller bars 4 freely rotatable upon inwardly projecting studs 5 provided on evenly spaced links. The chains s are held on the rims g h of the said wheels and prevented from separating laterally by circumferential flanges t, carried by the latter.

The paper sheet :23, see Fig. 3, passes from the parent paper roll 11, between the adhesive applying rolls 10 and through an opening 6 in the housing a onto the said roller bars '4 of the chains s, with the coated side outward. The sheet a: is carried on the said roller bars by the carrier wheels g, h from chamber b to chamber 0. Said carrier wheels are of large diameter, and the course of travel of the coated web is arranged to be very extensive so as to dry efliciently a large web. In chamber 0 the web leaves the chain s, and passes through an opening 11 in the housing a, over a cooling roll 12 carried by the frame 11 upon a shaft 12a and then to the rewind roll 13.

The carrier wheels 9, h are driven by the chain s and the paper sheet a: is carried on the roller bars 4,,of the chains 8 through the chambers b and c to the rewind roll 13. Thus the paper is supported for its entire length and its weight will not create a tension which coupled with the pull of the rewind roll would tend to break it.

The roller bars 4 being free to turn with the paper web permit local contraction in the web caused by the drying adhesive which would otherwise increase the tension of the paper to point at which it might cause the web to, break.

Also by these means the coated side of the sheet is positioned to be readily dried by a current of heated air, projected thru the encompassing hollow wall, the face of the latter overlying the coated side of the web being slotted.

Further, the idling rollers 2 in the passageway e are arranged to form an arcuate path for the paper and thus with the curvature of the wheels g, h maintain a tension on the edges of the paper and prevent them from curling inwardly, for adhesive coated paper will curl on the edges if carried in a straight line for a distance of six or seven feet or more.

Referring now to Figures 3 and 9 to 12, the housing a is provided with a, hollow wall providing air conduits 20 and 21 leading from a suitable blower fan 22 and entering the housing a at the top in the side of the connecting passageway e. The air conduit 20 connects with an air blast tunnel 23 located in the chamber b arranged close to but spaced from the chains s and the paper sheet carried thereby and is extended to encircle about 225 degrees of the wheel g, that is every portion of the wheel upon which the sheet a: is carried. The air conduit 21- is also connected with an air blast tunnel 24 similar in all respects to the air blast tunnel 23.

Said air tunnels 23, 24 are provided with transverse vents 25 and 26, respectively, see Figure 4, on the side adjacent the paper sheet. Preferably double heating elements 28 and a single heating element 29 is provided in the conduits 20, 21 so that the current of air blown through them by the fan 22 is heated and directed inwardly and radially upon the coated surface of the paper sheet to dry the same.

The hollow wall constituting air tunnels 23, 24 decrease in cross sectional area toward their extremities so that as the air escapes through the vents 25 and 26 the pressure is maintained along their entire length and an equal volume of air. is discharged through all the vents regardless of their distance from the fan 22.

Overflow or relief vents 30, 31 are provided in the tops of the chambers b, 0, see Figs. 4 and 10, which are open to the atmosphere, but are provided with shutters, 33, 34 adapted only to open outwardly by the pressure of the air within the chamber and thus prevents atmospheric air from being drawn into the chambers b,'c through the said vents.

Return conduits 35 and 36 are connected to vents 3'7, 38 provided in the side walls of the chambers b, 0 arranged midway between the top and bottom. The return conduits 35, 36 are connected to a mixing chamber 39 leading to the intake of the fan 22 so that the air after passing overthe web :r is recirculated, except the most humid which, rising to the top of the chambers b, 0 because of its lower density, escapes to the atmosphere through the overflow vents'30, 31. The remaining air which is drier is recirculated through the vents 3'7, 38 which are arranged at a lower level than the overflow vents 30, 31 and thus maintains the humidity of the air at a point greater than that of the atmospheric air to pre- 1 vent the adhesive from being over-dried.

- Whatever volumes of air are required to replace that discharged through the bverflow ducts, are 5 preferably drawn into the housing a through the various openings through which the paper sheet and the chains enter and leave the chambers b, c.

However, I provide doors 40 in the said mixing 150 chamber 39 so that additional atmospheric air may be drawn into the housing a in case the relative humidity of the atmospheric air should be so high as to require considerable volumes to lower the humidity, within the said housing to a point capable of drying the adhesive. I

Further, because the adhesive is partly dried by the time the paper web reaches the chamber '0, I have provided the single'heating element 29 in the conduit 21 and thus the temperature of the air entering the chamber 0 is lower and the tendency of the adhesive to become overdried is prevented.

Further, in order to prevent the paper from being wound on the rewind roll 13 while still warm, which might cause it to sweat, I provide.

the cooling roll 12 which is hollow and through which preferably cold water is circulated.

Iclaim:

i. In a machine of the character described, an

elongate housing, an endless driven conveyor having circular sections of large diameter located on opposite ends of the housing, and an arcuate bridging element between said circular sections, a supply reel and. a rewind reel located between saidclrcular sections of the conveyor, said conveyor arranged to conduct a web of material from said supply reel over an extensive course to a point adjacent said rewind reel, a hollow apertured wall inclosing the greater portion of said circular sections of the conveyor and. intermediate bridge section and means for projecting heated air currents thru said hollow wall.

2. In a machine of the character described, an elongate housing, an endless driven conveyor having circular sections of large diameter located on opposite ends of the housing, and an arcuate bridging element between said circular sections,

said conveyor comprising chains and transverse roller=bearing connections of said chains, a supply reel and a rewind reel located between said circular sections of the conveyor, said conveyor arranged to conduct a web of material from said supply reel over an extensive course to a point adjacent said rewind reel.

3. In a machine of the character described, an elongate housing, a pair of spaced, vertical carrier wheels of large diameter journaled in opp osite ends of said housing, a bridging element connecting the tops of said carrier wheels, a 

